- Body coverings (Skin and mucous membrane)
- Body secretions (Mucus, lysozyme in saliva, tears
and urine, sweat, sebum, ear wax, HCl …) - Body fluids (Blood and lymph)
- Skin :- The outer most keratin layer (protein)
prevents germs from entering it.
- Sebum makes skin oily and water proof.
- Sweat have disinfectants to destroy germs.
- Mucus and cilia in the respiratory tract prevent and
wipe out germs and dust. - Useful bacteria in skin and mucous membrane.
- Cough and sneezing to expel foreign bodies.
- Ear wax and hairs prevent the entry of substances.
- The enzyme, lysozyme, in the tears, saliva and urine
destroy germs. - HCl in the stomach fight against germs.
Action of WBCs :-
- Neutrophils – Engulfs and destroys bacteria,
Produces chemicals against bacteria - Basophils -Stimulates the other white
blood cells, Dilates the blood vessels. - Eosinophils – Destroys foreign bodies.
Produces chemicals for inflammatory
response. - Monocytes – Engulfs and destroys germs.
- Lymphocytes (B and T) act specifically against
antigens.
A. DEFENSE MECHANISMS IN OUR BODY
1.- Inflammatory Response
The dilation of the blood vessels by certain
chemicals, when a cut or wound occur, blood
flow increases to the wound site and more white
blood cells can reach there.
- Phagocytosis
[the process of engulfing and destroying germs
by certain white blood cells (phagocytes)] - Blood clotting
- Tissues of the wounded part degenerate to form
an enzyme, thromboplastin. - With calcium ions and vitamin K, thromboplastin
converts prothrombin to thrombin. - Thrombin converts fibrinogen to fibrin.
- In the fibrin net, RBCs and plateletes entangled
to form the blood clot.
- Healing of wounds
(When connective tissues form to heal the wound,
scar remains there) - Fever
Toxins of pathogens stimulate WBC to produce
chemicals for raising body temperature.
Fever prevents the rapid multiplication of bacteria
and increases the effect of phagocytosis.
Action of
B Lymphocytes
B lymphocytes, (which mature in the bone marrow)
produce antibodies, which destroy germs by
- disintegrating bacterial cell membrane,
- neutralising their toxins and
- stimulating the other white blood cells.
Action of
T Lymphocytes
T lymphocytes,(which mature in the thymus gland)
stimulate the other white blood cells and destroy
cancer cells as well as virus affected cells.
Lymph helps in defense mechanisms:
Lymphocytes in the lymph nodes and spleen
destroy bacteria
B. VACCINES for Induced Immunity
Vaccines are substances,given in advance to prevent
certain diseases.
Dead, inactive, alive but neutralized germs or toxins
are used as vaccines.
By the presence of these antigens, lymphocytes
become activated and produce antibodies. These
antibodies remain in the body for long time to
provide immunity against antigens.
[ Smallpox vaccine , the first vaccine, was invented
by the scientist Edward Jenner.]BCG, OPV, Pentavalent, MMR, TT are vaccines.
DIAGNOSIS & TREATMENT
Systems of medicine
• Allopathy (Modern Medicine) Hippocrates
• Ayurveda (A life style to maintain the body fit.
Majority of medicines are herbal. Indian)
• Homeopathy – Samuel Hanniman.
• Unani etc.
Some specialisation in Modern medicine :
Cardiology – (treatment of heart)
Ophthalmology – (treatment of eye)
Neurology – (treatment of brain or nerves)
Oncology – (treatment of cancer)
E.N.T – (treatment of ear, nose and throat)
Diagnosis
- Equipments (Stethoscope, Sphygmomanometer,
Digital manometer, Thermometer, ECG, EEG,
Ultra Sound Scanner, CT Scanner, MRI
Scanner, …) - Lab tests (blood, urine …)
Normal value of blood cells and haemoglobin :-
Haemoglobin – 12-17gm/100ml of blood.
RBCs count – 45-60 lakhs/ml of blood.
WBCs count – 5000-10000/ml of blood.
Platelets count – 2.5-3.5 lakhs/ml of blood.
Therapy - Using Antibiotics
Antibiotics are effective medicines used to resist
bacterial diseases.
The first antibiotics -penicillin – was synthesized by
Alexander Fleming (in 1928).
Side effects: - Regular use develops immunity in pathogens
against antibiotics. - Destroy useful bacteria in the body.
- Reduces the quantity of certain vitamins in the
body. - Radiation Therapy (for cancer and eye disease)
- Surgery
- Transplantation of organs
- Blood Transfusion
Carl Landsteiner proposed A,B,AB, O blood
grouping on the basis of A, B antigens seen on the
surface of the RBC.
Those blood with Rh factor (antigen D) on the
surface of RBC are termed as positive group blood
and those with out Rh are termed as negative group
blood.
If blood is not compatible, the antigen in the
received blood will react with the antibody in the
recipient’s blood of so as to clot RBC
(agglutination).
Defense Mechanisms in Plants
• Bark protects the inner cells.
• Cuticle and wax on leaves, defends the attack
of microorganisms.
• Cell wall, made up of cellulose, is rigid coat by
the deposition of lignin, cutin or suberin.
• Callose, a poly saccharide, prevents
the germs which have crossed the cell wall.